1. Field of the Invention
The present invention relates to a focus adjustment apparatus which includes a manual focus system and an autofocus system.
2. Description of the Prior Art
Compact digital cameras which include both a manual focus capability (manual focus system) for manually adjusting the focus by a photographer and a contrast detection autofocus capability (autofocus system) for automatically detecting a focus in accordance with contrasts of an object image are known in the art. In typical compact digital cameras, object images are captured at predetermined intervals and are indicated on an LCD panel. The manual focus system incorporated in such compact digital cameras is constructed so that a motor starts rotating upon a focus control switch being operated to move a focusing lens group in a direction toward a position thereof on the close-distance range side or the long-distance side by the rotation of the motor. In the case of performing a manual focus adjustment with such a manual focus system, the photographer operates the focus control switch while viewing an image indicated on the LCD panel. However, since conventional LCD panels are small in display size and also in number of pixels as compared with the number of pixels for photography (i.e., the number of pixels contained in an image pickup device such as a CCD image sensor), it is difficult for the photographer (user) to determine whether or not focus is achieved by the unaided eye while viewing an image indicated on the LCD panel.
A digital camera which has the capability of magnifying (zooming) an image indicated on a portion of the display area of the LCD panel has been developed (refer to Japanese Laid-Open Patent Publication (Kokai) HEI 11-298791). If such a zoom display operation is performed during operation of a manual focus adjustment, it becomes easy to visually determine whether or not focus has been achieved.
However, it is often the case that the focus of the focusing lens group overruns an intended stopping position even if the photographer releases the hand from the focus operation switch at the intended moment, and accordingly, it is difficult to bring the focus to a point intended by the photographer. Namely, it is difficult for the photographer to adjust the focus to a target point where the photographer visually determines that focus has been achieved.